Objective 1.2 – Identify vCenter high availability (HA) requirements

Continuing to my last blog post series, this blog will cover exam objective 1.2 i.e. identify requirement for vCenter server high availability requirements. VCHA is not covered in any other objective so I will be covering brief overview, deployment scenario and how to configure it in this part of blog. So let’s get started.

Overview of vCenter
HA Deployment

Before we can start with configuring vCenter server high
availability we need to understand different requirements as well as what can
be its deployment models. As vCenter server is available both as appliance and
Windows base solution, we will look at how to achieve high availability in both
scenarios. First we will talk about vCenter high availability in vCenter Server
Appliance (VCSA) and later on we will look at how to achieve vCenter high availability
using Microsoft failover clustering in Windows. I will cover vCHA in depth for
appliance base solution as this is main focus of exam.

vCenter High Availability
in VCSA

We can deploy vCenter server HA either using embedded
platform services controller or with external platform services controller. If
you are using external platform services controller, you can put it behind load
balancer for added protection against PSC failure.

vCenter HA with
Embedded PSC

When deploying vCenter HA with embedded PSC, deployment is
similar to below:

Passive vCenter: It is a clone of vCenter server, it receives updates from active vCenter and uses vCenter HA network to communicate with witness node.

Witness Node: It is lightweight clone of vCenter and used as a quorum to protect against split brain scenarios.

When cloning will start, it includes PSC services and data as well.

vCenter server will perform replication over vCenter HA network after cloning is complete to make sure that passive node is in sync with active node. In embedded deployment, it will send PSC data as well to passive node.

Once configuration is complete, vCenter appliance will be protected by vCenter HA and in case of host failure, passive node will take over and all services will be available from passive node.

vCenter HA with
External PSC

Deployment of vCenter HA with External PSC will be similar
to below diagram:

If you are using external PSC, then load balancer is
required to protect against failure of Platform services controller. If one PSC
goes down, then load balancer will redirect all request to second PSC.

Workflow of deployment:

First we need to setup two external PSC and configure load balancer to redirect request coming to load balancer VIP to PSCs. These PSC will replicate SSO domain information and other services with each other.

When deploying a vCenter server, we select external PSC and point it to load balancer VIP.

Enable vCenter HA using Setup vCenter HA wizard. Here setup can be done in two ways either automatic or manual.

If Automatic setup is selected, then cloning and configuration of network is taken care by vCenter server itself.

Step 8 – It will take some time and vCenter High Availability
will configured.

vCenter server for
Windows High Availability using Microsoft Clustering

If you are using vCenter server for windows and like to
deploy high availability then Microsoft clustering can be used to deploy a highly
available solution. We would explore this option under this configuration.

You can configure multiple instances in a cluster solution
but only one can be active at a time. MSCS solution can be configured only for
windows based vCenter server and doesn’t support appliance base vCenter server.
Also, it is supported only for VMs and doesn’t support physical server based
vCenter server.

Workflow to deploy vCenter server high availability using
Microsoft Clustering